Stanger nailed!!!!
The Argentina products have Extremely poor quality control. Some work, some don't. Machining on these are hit, and miss, and they seem to not care, as long as the bucks roll in.
A Rebuilt Bendix Control valve is 10 times better a product. Same goes to the ARGENTINA Steering Boxes as well.
I Believe those Binding, POORLY Machined Steering Boxes are worse than the Controls, and that is hard to do.
My favorite saying is:
To Fix the problem , remove the Argentina Piece, Making sure not to damage the ORIGINAL Fo Mo Co Parts it is attached to (Don't worry about the New Part, Take off anyway you can), Put in you car/truck, Drive straight to the nearest lake with a bridge you can drive over the water, Stop, get out, Throw the D-M thing over the railing, get back in, take a deep breath, you have solved your problem.
Dan
Classic Mustang Disc Brake Conversions and Power Steering